It is known to provide a controller for a motor vehicle arranged to check that an amount of torque developed by an engine of the vehicle corresponds to the amount of torque demanded by a driver of the vehicle. In the event that a discrepancy is identified the controller may be arranged to reduce the amount of torque developed by the engine.
In known vehicles, the amount of torque developed by the engine is typically measured by reference to engine speed and a flow rate into the engine of either air (in the case of petrol engines) or fuel (in the case of diesel engines). The values of engine speed and flow rate are then processed by a controller to determine the amount of torque being developed. This methodology for measuring torque has been found to be cheaper and more reliable than introducing a direct means for measuring torque such as a strain gauge on a crankshaft of the engine.
With the advent of hybrid electric vehicles (HEVs) having a plurality of prime movers including an engine and an electric machine, it has become necessary to measure the torque produced by each of the prime movers in order to determine whether the amount of torque developed by the vehicle corresponds to that demanded by the driver.